/**
 * Fig. 8.7: Date.java
 * 
 * Benito Dannes
 * 5 March 2017
 */

// Date class declaration
public class Date
{
    private int month; // 1 - 12
    private int day; // 1 - 31 based on month
    private int year; // any year
    
    private static final int[] daysPerMonth = // days in each month
        {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
        
    // Constructor: call checkMonth to confirm proper value for month;
    // call checkDay to confirm proper value for day
    public Date (int theMonth, int theDay, int theYear)
    {
        month = checkMonth (theMonth); // validate month
        year = theYear; // could validate year
        day = checkDay (theDay); // validate day
        
        System.out.printf("Date object constructor for data %s\n", this);
    } // end Date constructor
    
    // utility method to confirm proper month value
    private int checkMonth (int testMonth)
    {
        if (testMonth > 0 && testMonth <= 12) // validate month
        {
            return testMonth;
        }
        else // month is invalid
        {
            throw new IllegalArgumentException ("month must be 1-12");
        }
    } // end method checkMonth
    
    // utility method to confirm proper day value based on month and year
    private int checkDay (int testDay)
    {
        // check if day in range for month
        if (testDay > 0 && testDay <= daysPerMonth[month])
        {
            return testDay;
        }
        
        // check for leap year
        if (month == 2 && testDay == 29 && (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)))
        {
            return testDay;
        }
        
        throw new IllegalArgumentException ("day-out-of-range for the specified month and year");
    } // end method checkDay
    
    // return a String of the form month/day/year
    public String toString()
    {
        return String.format ("%d/%d/%d", month, day, year);
    } // end method toString
} // end class Date